The present invention relates to a velocity sensor for detecting a relative velocity with an object by emitting an electromagnetic wave and receiving a reflection signal of the electromagnetic wave reflected by the object and in particular, to a ground vehicle velocity sensor for detecting a velocity with respect to the ground by receiving a reflection wave from the ground.
Conventionally, there is known a velocity sensor using the Doppler sensor for detecting relative velocity with respect to an object. The sensor emits an electromagnetic wave or a supersonic wave to the object and receives the reflected wave, thereby utilizing the Doppler effect generated by the relative velocity with respect to the object. For example, there is a vehicle velocity sensor for correcting the ground vehicle velocity value obtained by the Doppler sensor according to the angular velocity around the center of gravity of the vehicle (for example, JP-A-9-264952).
Moreover, conventionally, there is known an on-vehicle supersonic wave measurement device for accurately detecting a vehicle speed by transmitting a supersonic wave signal from a supersonic wave transmitter to the road surface, receiving the reflected wave by a supersonic wave receiver, amplifying the received signal, and obtaining a reflected wave frequency from the amplified signal, wherein the supersonic wave transmitted from the supersonic wave transmitter to the road surface is focused on the road surface (for example, JP-A-7-260931).
Moreover, conventionally, there is a radar sensor including an active circuit such as an oscillator and a mixer and an antenna integrally formed on the same semiconductor substrate and configured on a single or a plurality of MMIC (Monolithic Microwave Integrated Circuit) chip, wherein the MMIC chip is sealed by a resin package, a dielectric lens is mounted on the upper portion of the antenna, and the lens and the resin package are integrally formed by a mold, thereby reducing the cost (For example, JP-A-2003-315438).